You will be asked (orally) to correctly answer six out of ten questions from the list of 96 official questions. In addition, you will be asked to write a (trivial) spoken sentence, and read aloud a (similarly trivial) written sentence.
The remainder of the interview will consist of you answering questions related to your N-400 application. At the simplest level this means confirming every line item as the IO steps through each section. If something draws the officer's attention, they may well dig into certain subject areas more thoroughly, and ask for backup documentation. (e.g. citations/convictions)